The Ditzies are small flying bioluminescent creatures who live in the caves of Fraggle Rock. They are the source of all light in the Rock. Somehow the Ditzies need the Fraggles' music to survive and the Fraggles need the Ditzies' light to stay awake. In the episode The Day the Music Died the Fraggles stopped singing and the Ditzies started dying, causing the light to go away and all Fraggles to go to sleep, except for Gobo, who sung his Glory Song just in time.